Thermostat Ratings

**Gatlin118391** · 10-22-2020

2011 RAM 3500 6.7
Deleted and tuned MM3 Tuner.

Stock thermostat 200 temp.
Installed 180 temp.

Should I keep stock thermostat temp?

Due to the ecm warmup mode or does my tuner affect it?

To my understanding my ecm doesn’t unlock full engine performance or working potential until coolant temp has reached its setting.

If the engine does not reach a high enough temp for the computer to leave warm-up mode then fuel economy will drop dramatically and your computer will not learn/work through the sensors as one.

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**Murph** · 10-29-2020

Originally Posted by Gatlin118391

2011 RAM 3500 6.7
Deleted and tuned MM3 Tuner.

Stock thermostat 200 temp.
Installed 180 temp.

Should I keep stock thermostat temp?

Due to the ecm warmup mode or does my tuner affect it?

To my understanding my ecm doesn’t unlock full engine performance or working potential until coolant temp has reached its setting.

If the engine does not reach a high enough temp for the computer to leave warm-up mode then fuel economy will drop dramatically and your computer will not learn/work through the sensors as one.

Mr Gatlin, I posted this and copied for ya from one of my earlier posts, and kinda cleaned it up for ya. I hope it helps....

I would, sounds silly, verify the t-stat for operation and correct temp rating. What part of the country are you in? When I brought my truck down from Wyoming (I live 40 miles north of Nogales Az.), I was giving it the once over and youtube'd all the the EGR cleaning vids and changed all the fluids to re-baseline etc. Well, since I had the EGR stuff out on my bench soaking, I decided to pop the t-stat out and found a 205. Pulled it out and op's checked with the ole boiling water and thermometer, my gauge and digital were approx equal but the t-stat wasn't opening til 220. So since i'm new to the diesel world, I drove to the Cummins maintenance and service center in Tucson, bypassing the clown show dealership close to me and talked at length about cooling and the dessert heat etc with one of the techs there and I mentioned changing the t-stat and going to a lower rating, I ended up going with a 180, and he said you may throw a light but thought it would be ok, LOL. Worked like a champ all summer and no issues......Then came our SoAz winter, more LOL BAM threw the light. Now got a 190 in and all is well. So much for experimentation. This was of course, before I stumbled across this site. I enjoy doing my own work and look forward to continuing my knowledge here and enjoy living vicariously through y'alls efforts and help and correction to keep these trucks doin' what they do! I hope ya find or have found the resolve for your issue and look forward to some of the returns to this thread as I'm sure i will be enlightened as I so often am here, thx and have a great week end!

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**Murph** · 10-29-2020

Originally Posted by Murph

Mr Gatlin, I posted this and copied for ya from one of my earlier posts, and kinda cleaned it up for ya. I hope it helps....

I would, sounds silly, verify the t-stat for operation and correct temp rating. What part of the country are you in? When I brought my truck down from Wyoming (I live 40 miles north of Nogales Az.), I was giving it the once over and youtube'd all the the EGR cleaning vids and changed all the fluids to re-baseline etc. Well, since I had the EGR stuff out on my bench soaking, I decided to pop the t-stat out and found a 205. Pulled it out and op's checked with the ole boiling water and thermometer, my gauge and digital were approx equal but the t-stat wasn't opening til 220. So since i'm new to the diesel world, I drove to the Cummins maintenance and service center in Tucson, bypassing the clown show dealership close to me and talked at length about cooling and the dessert heat etc with one of the techs there and I mentioned changing the t-stat and going to a lower rating, I ended up going with a 180, and he said you may throw a light but thought it would be ok, LOL. Worked like a champ all summer and no issues......Then came our SoAz winter, more LOL BAM threw the light. Now got a 190 in and all is well. So much for experimentation. This was of course, before I stumbled across this site. I enjoy doing my own work and look forward to continuing my knowledge here and enjoy living vicariously through y'alls efforts and help and correction to keep these trucks doin' what they do! I hope ya find or have found the resolve for your issue and look forward to some of the returns to this thread as I'm sure i will be enlightened as I so often am here, thx and have a great week end!

Here's the link to the thread in it's entirety Sir

2019 2500 POS

My computer skills are not excellent so type the above into topic search and it will take ya there if the link doesn't..

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**Murph** · 10-29-2020

Well Gatlin118391, I tagged that topic with your username, Desserttech started it. Sorry I'm not as computer savvy as the others here and great luck to ya Sir

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**AK Bob** · 10-29-2020

Originally Posted by Gatlin118391

2011 RAM 3500 6.7
Deleted and tuned MM3 Tuner.

Stock thermostat 200 temp.
Installed 180 temp.

Should I keep stock thermostat temp?

Due to the ecm warmup mode or does my tuner affect it?

To my understanding my ecm doesn’t unlock full engine performance or working potential until coolant temp has reached its setting.

If the engine does not reach a high enough temp for the computer to leave warm-up mode then fuel economy will drop dramatically and your computer will not learn/work through the sensors as one.

Great advice above, go with the 190*F or stick with the recommended stock 200*F and spend a little extra on the Mopar brand Part No.:68067109AB.

Unfortunately quite a few reports of issues with cheaper aftermarket replacements.

2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, Fuel Filtration Kit and 50 Gallon auxiliary fuel tank.

Sent from my iPad using Tapatalk

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